Tom @ Buzzard Bluff asked me to relay this information that may help with those old pumpers standing in the closet gathering dust.
Tom @ Buzzard Bluff wrote:
"A dry pump cup won't pump worth $hit and a gummy valve won't seal and hold. So by introducing a small amount of 30W ND, ATF, (preferred) Crosman or Daisy oil in front of the pump you do two things. You can often make the pump cup start sealing and compressing air which then forces the remaining oil into the sticky, gummy valve which will sometimes free up and seal. Both are usually short-term field repairs and a full teardown and reseal will still be in the cards in the near future. BTW----avoid 3-in-1 oil like the plague! It will eat seals!
A second and equally likely scenario is that the gun got cold overnight but warmed up from a lot of handling in the course of tinkering with it. Old, stiff seals---like old farts---aren't very compliant when cold and often refuse to work until warmed up----again like old farts. ;-) Careful use of a heat gun or hairdryer can often get old guns warm enough to get the cold out of their bones and joints and rejoin the living for a time. If you keep an old junker in garage or barn for convenient pest elimination and it quits working in cold weather a little time in the water heater closet or laundry room can sometimes work wonders too.
A few really violent pump strokes will also sometimes convince a stiff pump cup to expand enough to pump. Once it's pumping the heat of compression then helps it regain pliability and it will work fine----until next time.
Wannabe Bob recently rejuvenated an aging Benji pumper by introducing some oil and leaving it in a warm place for a few days or weeks at my suggestion. He reported back that it hadn't worked so I told him it was time for a rebuild but he's as hard-headed as some other people I know (like the one in the mirror ;-) ) so he gave it a 2nd dose and reported success. They don't get that way overnight so it takes time to revive them is my only observation in that respect. He'll still need a rebuild but now he knows it's a justifiable expense.
FWIW---a surprising number of ancient CO2 guns can be revived with what I call an ATF douche. It consists of simply introducing a few CCs of ATF into the CO2 chamber, pressuring it as much as possible with a charge of CO2 and dry firing it rapidly to distribute the ATF until the gas is exhausted or it starts holding. ATF is designed to keep O-rings and seals pliable so they can function in automatic transmissions and in old CO2 guns it seems to even revive old, hardened seals. A few years ago I bought a '50s era Crosman bulk-fill M-112 pistol complete with the original Crosman bulk CO2 tank very inexpensively at a local gun show because it wouldn't hold. I figured at its advanced age only a rebuild would cure it but tried the ATF douche on the ":nothing ventured, nothing gained" principle and it worked! So if you get a chance at an old bulk-fill Crosman cheap because it won't hold don't let that stand in your path. Come to think of it I did the same with a M-114 rifle of the same era a couple of years ago. I recently picked it up to see how much work it was going to require to refinish and on a whim cocked it and pulled the trigger. It was still holding and shooting like a cannon!
If this keeps up much longer I won't have any more magic secrets left for rejuvenating old CO2 guns and pumpers. ;-) "
Tom @ Buzzard Bluff wrote:
"A dry pump cup won't pump worth $hit and a gummy valve won't seal and hold. So by introducing a small amount of 30W ND, ATF, (preferred) Crosman or Daisy oil in front of the pump you do two things. You can often make the pump cup start sealing and compressing air which then forces the remaining oil into the sticky, gummy valve which will sometimes free up and seal. Both are usually short-term field repairs and a full teardown and reseal will still be in the cards in the near future. BTW----avoid 3-in-1 oil like the plague! It will eat seals!
A second and equally likely scenario is that the gun got cold overnight but warmed up from a lot of handling in the course of tinkering with it. Old, stiff seals---like old farts---aren't very compliant when cold and often refuse to work until warmed up----again like old farts. ;-) Careful use of a heat gun or hairdryer can often get old guns warm enough to get the cold out of their bones and joints and rejoin the living for a time. If you keep an old junker in garage or barn for convenient pest elimination and it quits working in cold weather a little time in the water heater closet or laundry room can sometimes work wonders too.
A few really violent pump strokes will also sometimes convince a stiff pump cup to expand enough to pump. Once it's pumping the heat of compression then helps it regain pliability and it will work fine----until next time.
Wannabe Bob recently rejuvenated an aging Benji pumper by introducing some oil and leaving it in a warm place for a few days or weeks at my suggestion. He reported back that it hadn't worked so I told him it was time for a rebuild but he's as hard-headed as some other people I know (like the one in the mirror ;-) ) so he gave it a 2nd dose and reported success. They don't get that way overnight so it takes time to revive them is my only observation in that respect. He'll still need a rebuild but now he knows it's a justifiable expense.
FWIW---a surprising number of ancient CO2 guns can be revived with what I call an ATF douche. It consists of simply introducing a few CCs of ATF into the CO2 chamber, pressuring it as much as possible with a charge of CO2 and dry firing it rapidly to distribute the ATF until the gas is exhausted or it starts holding. ATF is designed to keep O-rings and seals pliable so they can function in automatic transmissions and in old CO2 guns it seems to even revive old, hardened seals. A few years ago I bought a '50s era Crosman bulk-fill M-112 pistol complete with the original Crosman bulk CO2 tank very inexpensively at a local gun show because it wouldn't hold. I figured at its advanced age only a rebuild would cure it but tried the ATF douche on the ":nothing ventured, nothing gained" principle and it worked! So if you get a chance at an old bulk-fill Crosman cheap because it won't hold don't let that stand in your path. Come to think of it I did the same with a M-114 rifle of the same era a couple of years ago. I recently picked it up to see how much work it was going to require to refinish and on a whim cocked it and pulled the trigger. It was still holding and shooting like a cannon!
If this keeps up much longer I won't have any more magic secrets left for rejuvenating old CO2 guns and pumpers. ;-) "